It's legal on highways, e.g. "any roadway on which traffic is restricted to one direction of movement" https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXI

It's legal on highways, e.g. "any roadway on which traffic is restricted to one direction of movement" https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXIV/Chapter89/Section2 https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXIV/Ch... I lived in Massachusetts for 3 years and routinely passed people on the right, sometimes even in the breakdown lane if it was open for traffic.